Beginning Web Development With Perl : From Novice to ... - Nabo

CHAPTER 5 ■ LWP MODULES 99Recall that the default is 180 seconds. You can set the timeout either when you create thebrowser object or at any time during its life. Assume you have a browser object called$browser. In this example, you set the timeout to 30 seconds, instead of the default 180:$browser->timeout(30);Controlling Browser RedirectsBrowser objects created through the LWP::UserAgent class accept HTTP redirects for the GETand HEAD methods. You can change this behavior to accept redirects for other combinations ofHTTP methods or disallow redirects entirely. The requests_redirectable attribute acceptsa list of HTTP methods that can be redirected:$browser->requests_redirectable([\@methods]);This list is inclusive, so if you merely call the function with one method as an argument,you overwrite what’s already there. To accept redirects for the POST method (discussed in the“Submitting a Web Form” section a little later in this chapter), you add it to the list by callingrequests_redirectable:push @{$browser->requests_redirectable}, 'POST';Realize that the requests_redirectable attribute already contains two values: GET andHEAD. Therefore, if you want to add a method to that list, you must use a method such as push(as in this example). If you don’t push a new value onto the stack, you’ll be replacing what’salready there. This can cause no end to confusion.Based on that note of caution, it’s sometimes helpful to see if a particular method willindeed accept a redirect for a given browser object. A call to the redirect_ok() method willreturn true if a redirect would be permitted for the given method. Consider this example:if ($browser->redirect_ok(GET)) {print "The browser object would accept a redirect for GET\n";}Sending Additional HeadersIn some cases, you may need to specify additional header lines as part of the request for a URL.In these instances, you can send them along with the request as key/value pairs. For example,a GET method using the get() function would normally look like this:$browser->get($url);To include additional headers, place them after the URL, as in this example:$browser->get($url, Header => Value, Header => Value . . .)A use for this might be to send the acceptable character set to the server:$browser->get($url, 'Accept-Charset' => 'iso-9859-1');Cloning the BrowserIf you already have a browser object set up in your program and configured as you like it, youcan use the clone() method to quickly create a duplicate of the browser object. Assume that